Accountability is key (in my opinion) and, no, he does not "need" to go to meetings to be sober but they do help in most cases.

If he is willing to have a close sober friend be an accountability partner with him then he will have an easier time staying sober. Someone he can hang out with, call, text, message, etc if he has the urge.

Spending time alone is NOT a good thing for one in recovery and getting him out of the house and staying busy is important.

Sobriety is not easy alone, it takes support however that is achieved.